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MT-32 Montana Grazing Animal Unit Month (AUM)/Acre Estimator

Range and Pasture Technical Note Number MT-32 (Revision 2)

A printer-friendly versions of this technical note is available in Adobe Reader format:
Range and Pasture Technical Note Number MT-32 (Revision 2)(PDF; 68 KB)

Revised September 2008

Background

Rangeland and dryland pasture Animal Unit Month (AUM) estimations are needed for a variety of conservation planning and data applications.

Anticipated Use of the AUM Estimator

  • Montana Department of Revenue - Application for Agricultural Classification of Lands. AUM calculations must use the Below Normal AUM/Acre values for qualifying agricultural land.

Definition of AUM/Acre Parameters

  • Below Normal AUM/Acre values – lower precipitation and possibly cooler temperatures at a critical time that leads to lower production for the historic climax or near climax plant community. These AUM/Acre values should be used for AUM estimation where the plant community is at less than the historic climax or near climax condition or similarity index.
  • Normal AUM/Acre values – precipitation and temperature that allows for normal plant production for the historic climax or near climax plant community.
  • Above Normal AUM/Acre values – higher than normal precipitation as well as adequate temperatures that allows higher plant production for the historic climax or near climax plant community.